Word Biblical Commentaries are generally not my favorite. BUT since there's no theological library here, I use what I got, and what I got are Anchor and Word, each in partial set.
Word vol 35b!!! by John Nolland. On the parable of the Good Samaritan. Page 597. be with me, folks -- it's amazing --
The lawyer asks, "who is my neighbor?" Jesus suggests that we should answer that question from a vantage point of isolation and desperate need
(i.e. ask -- if I were lying in a ditch near-dead, who would I look for to be a neighbor? anyone.)
and then make use of that same answer
(who's my neighbor? anyone)
when we come to the question from a position of strength, when it is within our gift to be handing out favors, rather than receiving them (when someone else is in the ditch and we are not).
Amen and amen!
I interpret this further. "What does the law say?" was the original question, the original answer "love God and neighbor," counterquestion "who is my neighbor?" and counteranswer "think about it from the other side."
I interpret it further (but not much further -- jesus spoke in medical terms too, and addressed it to a lawyer) -- If I were lying in a hospital ditch without insurance, my neighbor would be anyone who could help me -- be it a church holding a pie auction to raise funds, or a lawyer proving that I and my comrades in uninsurability deserved care NOW, not later.
I interpret it further. "How should I show love to my neighbor?"
Think about it from the other side. If you were a victim, how would you want love shown?
and you'll often find that victims don't sit around philosophizing. Often the answer is "JUST HELP NOW!!!"